- The aftermath of World War I: The US emerged from World War I with a strong desire to avoid future conflicts. The war had been devastating, both in terms of human life and economic resources, and many Americans were opposed to the idea of intervening in other countries' affairs.
- The rise of isolationist sentiment: Isolationism was a popular sentiment in the US throughout the 1920s and 1930s. Many Americans believed that the US should focus on its own domestic problems rather than getting involved in international affairs.
- The Kellogg-Briand Pact: In 1928, the US signed the Kellogg-Briand Pact, which outlawed war as a means of resolving international disputes. This pact reinforced the US's commitment to isolationism and helped to create a sense of security among Americans.
However, the US's policy of isolationism ultimately proved to be unsustainable. In the late 1930s, the rise of fascism in Europe and Japan led to a renewed sense of urgency among Americans. The US eventually abandoned its isolationist policy and entered World War II in 1941.